1. Field
Various features pertain to ultra wideband communications. At least one aspect pertains to an ultra wideband transceiver having improved low-power consumption.
2. Background
Ultra-wideband (UWB) is a radio technology that can be used for high-bandwidth communications by using a large portion of the radio spectrum (e.g., bandwidth of 500 MHz or greater). UWB communications transmit in a way that does not interfere largely with other more traditional “narrow band” and continuous carrier waves in the same frequency band. Generally, the Federal Communications Commission (FCC) defines UWB as a system using a bandwidth that exceeds the lesser of 500 megahertz (MHz), or 20% of the center frequency. The FCC uses −10 dB emission points to determine bandwidth, and to define the center frequency. UWB technology may be applicable to high and low data rate personal area networks (PANs). The advantage of the large bandwidth is that the system should be able to deliver high date rates over short distances, while sharing the spectrum with other communications systems. For this reason, the FCC has authorized the unlicensed use of UWB in the band between 3.1 gigahertz (GHz) and 10.6 GHz. UWB can be generated as a pulse type system, where each transmitted pulse occupies the entire UWB frequency bandwidth. An aggregation of narrowband subcarriers are used to generate at least 500 MHz of frequency bandwidth. For example, an orthogonal frequency division multiplexing (OFDM) system may be used. OFDM splits the digital information to be transmitted over a plurality of parallel slower data rate streams. Each of the parallel data streams is modulated onto a particular subcarrier, using a technique such a quadrature phase shift keying (QPSK) for example, and transmitted at a relatively low data rate. The subcarrier frequency is chosen to minimize crosstalk between adjacent channels, which is referred to as orthogonality. The relatively long symbol duration helps minimize the effects of multipath, which is the degradation caused by signals arriving at different times.
The UWB European Computer Manufacturers Association (ECMA) 368 standard is an example of a wireless standard that seeks to implement UWB.
One challenge with the current UWB technology is that it may consume too much power to be efficiently implemented on mobile devices (e.g., mobile phones, personal communication devices, mobile computing devices, etc.) that have limited power sources. That is, current consumption of UWB transceivers may not be suitable for mobile devices.
Consequently, improvements to UWB transceivers are desirable to achieve lower power consumption. Preferably, such improvements to UWB transceivers would substantially comply with, or are compatible with, existing UWB standards.